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Ln_mark7930
Joined: 06 Mar 2009 Posts: 21
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sx19v001 Color display with touch screen |
Posted: Wed May 13, 2009 4:10 am |
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hi boys!!!
I have only a simple question:
I bought for only 15 Euros a wonderfull color display
(640*480 pixel with touch screen).
If you see the datasheet (http://www.rgmelsat.com/display_lcd/sx19v001.pdf), you can find the diagram which show how you must send data and move every signal.
I don't understand how draw a pixel in glcd because I can't understand the table on page 12 and 16. Can someone tell me some explanation??
Thank's at all.
mark |
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andyfraser
Joined: 04 May 2004 Posts: 47 Location: UK
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sx19v001 Color display with touch screen |
Posted: Wed May 13, 2009 6:46 am |
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Hi,
I would suggest the display is cheap because it does not contain a controller to manage driving the panel.
Consider your 'little' PIC clearing the 640x480 screen, that would take a write of 307 thousand bytes !
Andy |
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Ln_mark7930
Joined: 06 Mar 2009 Posts: 21
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i know |
Posted: Wed May 13, 2009 7:10 am |
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Thank's for answer to my question.
I know which my display hasn't controller on board.
and I know that I must write code to manage every little command...
Do you understand how can I draw one pixel?
For example: how i must send data and command to write one pixel (x,y) 20,20? and the informations of colors? |
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andyfraser
Joined: 04 May 2004 Posts: 47 Location: UK
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sx19v001 Color display with touch screen |
Posted: Wed May 13, 2009 8:33 am |
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Hi,
Assuming you wanted to change the top left pixel, you would put your combination of RGB bits onto an 8-bit port (D0..D7 on the LCD) then set the frame and pixel clock lines accordingly. However, you cannot address a particular pixel without a controller so you would need to write EVERY pixel every frame thus you need a super fast PIC with 307,200 bytes or RAM !
Andy |
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John P
Joined: 17 Sep 2003 Posts: 331
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Posted: Wed May 13, 2009 10:16 pm |
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With a display of this type, you are responsible for sending data at the specified frame rate (about 100/sec), in the correct pattern to fill each of the 480 lines in sequence, plus 17 extra dummy lines. The data has to be delivered in sequence R, G, B, R, G, B etc, 8 bits at a time, which means that the color sequence won't match the edges of bytes; instead it repeats every 3 bytes. The average data rate seems to be about 12 megabytes per second, but it doesn't need to be uniform, as long as the line-sync pulses (CL1 on Hitachi's data sheet) are at a constant rate.
You have no hope of getting a PIC to do this directly. It hasn't got the memory capacity or the speed. You would need to set up an external clocking system and memory, which the PIC might control. But I think this would be a very challenging project. The right way to ccntrol this display is with a programmable logic chip, a CPLD or FPGA or something of the kind. |
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arunb
Joined: 08 Sep 2003 Posts: 492 Location: India
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Re |
Posted: Fri May 15, 2009 5:51 am |
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maybe Hitachi has a controller for the display.... |
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